9 Dec 2016

Differences between male and female brains in autism

Dr Melissa Kirkovski

by Anne Crawford

Australian males are estimated to be four times more likely than females to be
diagnosed with Autism Spectrum Disorder (ASD). The mechanisms that make them
more prone to the condition are currently a hot topic of research in the field.

A former Central Clinical School (CCS) graduate student was part of a study by the MonashAlfred Psychiatry research centre (MAPrc), the CCS and others that found gender
differences in a region in the brain implicated in social understanding – a
core part of impairment in people with ASD. The research was part of a PhD
thesis that later earned Dr Melissa Kirkovski an international award.

Dr Kirkovski
used fMRI (functional Magnetic Resonance Imaging) to investigate differences between
the sexes in brain activity in adults with high-functioning ASD, comparing this
with a control group of people without the condition. She was supervised by
Professor Paul Fitzgerald at MAPrc and Associate Professor Peter Enticott from
Deakin University’s Cognitive Neuroscience Unit.

“At the time
we set up the study there was a little bit of literature indicating there were
differences between males and females with autism at a brain-based level but it
was unclear what these differences were,” Dr Kirkovski said. “We wanted to take
this a step further and see whether or not there were any functional
brain-based differences and where these differences were located,” she said.

The
researchers showed 50 participants videos with two floating ‘characters’
that interacted physically and emotionally, testing brain activity as they
watched using fMRI.

The fMRI
showed that males with ASD had reduced brain activity in the posterior superior
temporal sulcus, a part of the brain strongly implicated in social
understanding, but there was no evidence of this in females with ASD.

“This was a
novel finding at the time, not reported previously,” Dr Kirkovski said.

“It was one
of the early studies looking at the functional neurobiological underpinnings of
sex differences in autism. It’s suggesting that we need to look more closely at
this,” she said.

The study concludes
that the findings could serve as an important guide for future brain-based intervention for autism.

“Understanding
the differences between the sexes is really important for understanding how we
diagnose Autism Spectrum Disorder and, in the future, how we treat it,” Dr
Kirkovski said. “Further research would also help us tailor treatment to clinical
needs,” she said.

The study was
part of a PhD project that earned Dr Kirkovski, a neuroscientist, the 2016
International Society for Autism Research (INSAR) Distinguished Dissertation
Award, which she received at the society’s annual conference in Baltimore in May.

She said that
researchers at conferences elsewhere have also expressed interest in the study
and that the study participants appreciated it.

Dr Kirkovski
is now a research fellow at Deakin
University's Cognitive Neuroscience Unit.